Engine killing starter motors?!

Location
UK
OK, I'll try and describe this as briefly as possible:

Rebuilt SJ 62T 760 engine over winter.
When I first tried starting the engine I found it wasn't cranking.
Bought a new starter, reconditioned the OEM motor.
Turns out it was the wiring to the starter, replaced all battery, starter and earth cables with new.
Got engine run in.

After about 2 hours of use, I took the ski out recently, it cranked fine and I rode for it 10 mins. Came off and it wouldn't crank. Could hear the solenoid clicking. Got a tow back to shore.

Back at the workshop, I took the starter motor out and I couldn't turn it by hand or with pliers. Not good, but it wasn't OEM and I've heard bad things. Turns out the roller bearing was shot.

I put the reconditioned OEM motor in and gave the engine a good crank. There was a little moisture in the engine presumably from the tow back, so it took 20 mins of cranking/drying plugs/cranking again before she would start.

Got the engine fired up and ran it for a minute or two to blast out as much water as I could.

Go back the next day, hit the starter button, and it doesn't crank. Can just hear the solenoid click.

Take the reconditioned motor out and it still turns, just, but is really stiff. Bearing & bushing are fine, but it's actually stiff inside the main magnets section. Another dead starter motor.

Pull off engine front cover: no damage to any bendix or flywheel teeth. Bendix appears to be working completely smoothly and without issue, though I'm not too sure how to test these, other than check the gears move forward smoothly, etc.

Took electrical box apart (maybe some weird electrical issue where starter is re-engaging when engine is running) and checked all connections. All looks just fine. Naturally ensured battery is strong and charged, and tried a second, known good, battery.

Any ideas whatsoever where to go from here? I'm utterly stumped and I don't want to gamble more 200 quid starter motors on it being fixed.

On top of that, I've not been able to run the engine properly after having some moisture in it, and I'm super-worried it's going to be ruined.

Not loving jet skis right now!

Thanks in advance.
 
If the bendix kicks in and out freely by hand, and still has the internal spring, it's most likely fine. If the flywheel doesn't have grind marks on the teeth, the starter isn't running while the engine is running. I have had bad luck with starters also. The are pretty easily rebuilt though. Believe it or not, I've had the best luck with 2 aqua torque starters that I got in used skis. The damn things won't die at all.

Sorry I couldn't offer more info for your problem. It's possible cables are bad and causing a problem, but you said you replacd them. Post up if you find the problem.

Edit; I always yamabond the starter snout and the flywheel cover. I don't even run a flywheel gasket anymore because of water intrusion there ever since going to straight yamabond it's always bone dry and looking factory new inside.
 

OCD Solutions

Original, Clean and Dependable Solutions
Location
Rentz, GA
You could have an issue with the solenoid itself. If you jump the terminals with a screwdriver does it crank normal?

Also, what did you use to replace the OEM cables? Did you buy OEM again or make something up yourself? If home made, inspect to make sure they are still holding up. Alot of current flows thru them and if things aren't just right, you can cook them fast.
 
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